This CDC sponsored protocol evaluates rifapentine pharmacokinetics and risk factors for relapse among HIV positive and select HIV negative participants in the Rifapentine Clinical Trial. The objectives are to study INH and rifamycin pharmacokinetics; to define INH acetylator status in HIV+ participants and all participants who have experience failure or relapse; to ascertain the bioavailability of INH and rifapentine/rifampin; and to compare the use of urine and blood for pharmacokinetic screening.